Marking pen



FIG. 1 is a perspective view of a marking pen showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a front view of the body thereof shown without the cap for convenience of illustration;

FIG. 6 is a left side view thereof shown without the cap for convenience of illustration;

FIG. 7 is a right side view thereof shown without the cap for convenience of illustration; and,

FIG. 8 is a back view thereof shown without the cap for convenience of illustration. 

CLAIM The ornamental design for a marking pen, as shown and described. 